


Good Boys Are Fast Learners

by Michi27



Category: Supernatural
Genre: Alien Castiel (Supernatural), Alternate Universe, Anal Fingering, Anal Sex, Bisexual Dean Winchester, Blow Jobs, Bottom Dean Winchester, Castiel Has a Large Cock (Supernatural), Cock Slut Dean Winchester, Come Eating, Come Swallowing, Come as Lube, Creature Castiel (Supernatural), Dean's a needy bottom, Dumbasses, Enthusiastic Consent, Enthusiastic Dean Winchester, Face-Fucking, Fluff and Smut, For the purposes of this fic anyway, Gay Virgin Dean Winchester, Hung Castiel, Kind of still hunter Dean, M/M, Mind Your Tags, Multiple Orgasms, Naive Castiel (Supernatural), Naked Cuddling, Porn With Plot, Rimming, Rough Oral Sex, Rough Sex, Smut, Top Castiel (Supernatural), Top Castiel/Bottom Dean Winchester, Virgin Castiel (Supernatural), but he's practically human, but of aliens, but seriously, consent kink, hang onto your hats, hoo boy, mentioned deceased John Winchester, ok, ok I THINK I got everything, only the bad ones, oversensitivity, smluffy, the first two chapter are almost entirely porn, there's a little fluffy epilogue, time for the tags, trenchcoat kink, yep more pwp
Language: English
Status: Completed
Published: 2020-02-18
Updated: 2020-02-18
Packaged: 2021-02-27 22:02:11
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 10,496
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22792927
Author URL: https://archiveofourown.org/users/Michi27/pseuds/Michi27
Summary: “C-Can I…?”Cas blinks those big, dark, sweet icing blue eyes. “What would you--”But he fits his lips to Cas’ without waiting to hear his question--let alone answer it, butterflies exploding in his stomach and climbing up his throat until he moans, knowing he’s taking Cas’ first kiss--knowing Cas has never done or feltanythinglike this before and Dean gets to have that.Hegets to have that. His.His. And shit, but he wantsallof Cas’ firsts.***Or, Dean’s been wanting Cas for so long, and now that they’re finally free, he’s going to have him.
Relationships: Castiel & Dean Winchester, Castiel/Dean Winchester, Destiel
Comments: 31
Kudos: 443





	1. Chapter 1

**Author's Note:**

> Did you read the tags? Okay, cool. This is all very enthusiastic, but there’s a lot of kinks in here, so please mind them xD
> 
> My intense gratitude goes to my friends, [@msufangirl](https://twitter.com/msufangirl) and [@IPutTheDInDean](https://twitter.com/IPutTheDInDean) for giving me the boost I needed to post this, and for reading it ahead of time and yelling at me about it (I lube you ladies). So if you read this and you like it, go thank them for being freaking amazing 💙💚💕
> 
> Now, I know you’re just skimming this to get on with the good stuff, so I’ll stop holding you up. Warning: this fic may make you horny 😏

They weren’t all bad, some of them were good. A few of them. Cas… Cas was good. He’d saved Dean’s freaking life from his own people so many times, and now that it was over, now that it was all over, and they’re here in this stupid warehouse and Cas’ people are _gone_ … Now that they’re gone through that damn portal, to some other planet and Cas is still _here_ , here with him. Alone. Alone with him. Deserted. And it’s _over_ , Dean looks at Cas breathlessly, looks at this freaking _alien_ , hunched over in his beige tax accountant trenchcoat, blue eyes sad, relieved, happy at the same time, and lips all chapped because he doesn’t know what the hell human-made chapstick is, but firm and pink in their almost quirked, almost smiling line. Now that everything that’s happened since the day he met Cas has led him here, to this moment, Dean’s never wanted anything as much as he wants Cas right now. Right, fucking here.

He swallows thickly, or tries to, though it doesn’t really go down very well because _god_ , he wants him. Like, maybe it’s partially the adrenaline still shaking through his fingers, but he wants him so bad his stomach is clenching and his cock is hardening in his pants, these pants he hasn’t changed for two days because they’ve been running and fighting and collecting the ingredients to open this damn portal and shove everything through for so long he’s hardly had the chance to sleep or eat, and somehow this desperate, impossible plan has finally _worked_ , and he’s free-- _they’re_ free. And now, now all he wants is Cas. Want Cas’ clothes _off_. Wants skin. Wants his weird musk filling his nose.

Wants his virginity.

His shotgun clumps and thumps on the dusty wood floor, dropped and forgotten because he can’t wait anymore, can’t wait and whatever leftover adrenaline there is in his young body pumps through his veins as he crosses to Cas and puts one hand on his neck and the other on his crotch, and he says, “Cas, Cas,” so close he knows his breath must be blowing over Cas’ perfectly plump cotton candy lips. “You know what sex is, right?”

Those big, gorgeous eyes open wide, surprised, confused, a flare of something _else_ deep in them as they flick down where Dean’s running his palm. And shit, by the way, Dean’s biting back a _groan_ because Cas shaped himself _big_. Shit, he’s hella _big_.

“S-Sex?” Cas asks carefully. “You mean copulation to the production of-of offspring?”

And Dean huffs a laugh and shakes his head because of course that’s what Cas would think. _Of course_. Of course his big, naive, genius, idiot, gorgeous alien would think sex is only for reproduction.

There’s so much more to show him. A blush streaks across his cheeks. “You said-said whatever shape you had before, you were like--I dunno--fish or somethin’, yeah? Somethin’ like that. No dicks. Dickless.” He chuckles again, feeling delirious, feeling drunk on Cas’ heat. On the heat burning under his palm, hardening, thickening--oh fucking hell. His fingers make shapes in Cas’ neck, his eyes flicking down to his mouth, wanting him, wanting him, oh. 

“Sex is different. You don’t have to-to make kids,” he grunts, endlessly distracted. Wanting to taste, so bad. But Cas is so naive. Even more so than he is, virgin they both are. Well, kinda. But is this bad? Is he bad? Should he--

He bites his cheek, not wanting to stop. Torn. But not wanting to stop. Not ever stop being this close to Cas. Or sliding his fingers around the bulbous head between layers of silky pants and boxers. Shit, he’s the idiot--shouldn’t be doing this, at least not _here_. And yet…

“Sex can just be about _feelin’ good._ And-And making someone _else_ feel good. And fuck, Cas, I’m a virgin too--well, kinda. I’ve been with a girl a coupla times, but never with a guy. I just haven’t had the freaking time.” Or maybe he had never met the right guy. Maybe-Maybe the right guy hadn’t been on his planet yet. And that’s sappy, sappy shit, but also? Is it true? He thinks it’s true, he’s pretty _sure_.

“But I’ve read about it. A whole fucking lot. And I want you so _bad_ I can’t think straight right now. C-Can I…?”

Cas blinks those big, dark, sweet icing blue eyes. “What would you--”

But he fits his lips to Cas’ without waiting to hear his question--let alone answer it, butterflies exploding in his stomach and climbing up his throat until he moans, knowing he’s taking Cas’ first kiss--knowing Cas has never done or felt _anything_ like this before and Dean gets to have that. _He_ gets to have that. His. _His_. And shit, but he wants _all_ of Cas’ firsts!

But, hell, he realizes what he’s doing--kissing without asking or waiting for a response, which is so, _so_ not him, and doubt flickers in his chest. He pulls back sooner than he wants, not knowing if this is any good, if it’s okay, if Cas even _wants_ this (as hard as he’s getting in his slacks), and please God, let him want this, but he has to see, he has to ask, to know for sure.

Drawing in a breath to clear the fog on his thoughts, he sees Cas’ eyes are slightly widened when Dean parts enough to look at him. And Dean is breathless, even now looking at him, even from that small kiss, but still he says, “Was thinkin’ we could--” but Cas kisses him, kisses him back before he can finish, and it’s a little messy, a little rough, a little misaligned, but it’s still Cas. Kissing him. And it’s still _good_. Definitely, very, very, oh so good.

Dean blinks open his eyes when he’s released, trying to focus, trying to breathe, trying to _think_. “We-We could--was thinkin’ maybe we could… kinda teach each other and--” Cas has this look in his eyes, though. It’s like, it’s surprise and maybe curiosity, but also--also--burning, burning, like something’s on _fire_ inside, and he kisses him again, cutting him off again, and Dean can’t even be mad because he taught him that himself not two minutes ago.

A bubble of mirth rises up his throat, tickling his lips, and he almost laughs. Almost. Kiss first, ask questions later. God, he’s giddy. But Cas is already learnin’.

“Y-You said this shape you got now--” Dean continues, his voice slightly slurred when Cas gives him a breath. “It’s--” Cas turns his head this time for a little change when he presses their mouths together, and it’s softer and wetter, and Dean just _wishes_ the room would stop spinning so he could think straight, but then maybe it’s not the room--maybe it’s Cas, kissing him back. Kissing him _back_. Good. _Really_ good. Did he mention Cas is a fast learner? Like, the way he picked up shooting and spellwork blew Dean’s fricken mind. Such a quick, _quick_ learner, always such a good student. Eager to get it right. Would do it again and again until he was satisfied. 

“The-The shape--body--this body,” Dean tries, the hand that been teasing Cas’ cock to life somehow having migrated to Cas’ hip instead (probably to hold on better), now squeezing. “Is your real, permanent body now?” Those big blues--well they’re really more like big blacks now--are trained on Dean’s lips, and he’s not even sure Cas heard him when he kisses him again without answering, his big hands going to Dean’s sides, his neck, his cheeks, brushing, brushing, brushing his cheeks. Dean would collapse without those hands on his cheeks.

But, “Yes,” he answers, though it takes a really long second to figure out what it is he’s answering to. “I can no longer shape shift. This is-This is me now.” He tears his eyes from Dean’s face for the first time since Dean cornered him and looks down at himself. “Does this body please you?”

“Mmm,” Dean hums, neither agreeing nor disagreeing, tasting Cas on his lips, sweet and odd, like his weird, musky, addictive scent. Foreign. Alien. He immediately likes it. “What I like most is the guy inside. The--” he doesn’t try to pronounce the name of Cas’ people, that series of long, elegant silvery syllables that don’t fit on his crass tongue, but instead says, “--the _Cas_ inside. I like _you_ , Cas. But shit, if I’m being honest, you picked one _hell_ of a body.”

Cas’ lips crush into his, but this time, Dean’s ready for him. Or as ready as he can be to be kissed by a sexy alien, but he kisses back hard, and this time, sweeps his tongue across Cas’ lips and dips inside when he opens, meeting Cas’ tongue, and _grinding_ against it hungrily, and _feeling_ Cas’ groan more than hearing it.

Fuck. Fuck. Is he really doing this? His fingers twist sharply in Cas’ hair, and he kisses him deeply, probing his own mind and heart and soul. He _wants_ Cas, but is he really doing this? Is he really gonna fuck an alien? Sure, Cas is nearly human. Kinda. Aside from the, you know, strength. And the talking to plants and animals thing. _And,_ he thinks, as something long and hot and hard brushes his thigh, _the monster cock apparently_. But he’s still an _alien_.

Dean searches himself further, thoughts flicking to his little brother, sixteen years old, but a fricken genius, and he knows immediately he’d support him. Considers for a second his dad and figures if he were still alive he’d call him a brainless, stupid kid, but even as his heart gives a pang, his dad is not here and not alive, and even if he were… This is _Dean’s_ choice to make. His choice, and fuck him, but he chooses _Cas_.

Cas is good. Cas is _good_. Loyal. Brave. Kind. Determined. Heart of fricken gold, and Dean’s known him long enough. Long enough--almost two years, and shit, if he’s telling the truth, he thought he was hot as fuck the day he met him in those ruins. Even when he didn’t trust him, wouldn’t consider letting himself do something like this--even then. And it’d been a long ass time since he’s wanted to kiss him, just like this. Just. Like. This.

God. There’s nothing there, nothing to hold him back. They’re safe. Cas is here. Cas _stayed_. He’s free. Free to kiss him for as fucking long as Cas will let him. And they have so much time to make up.

“Cas,” he almost chokes, breath stolen, “tell me you want this,” shoving his knee at that long, thick heat between his legs even as he asks it, his stomach flipping when a sound of surprised pleasure slips from those plush, darkened lips. The floorboards creak under them as they stumble to the wall. 

“Dean,” Cas practically _moans_. “I want this--I want _you_. I want this very much, but I--” he stutters, breath rough like he’s already fucked him. “I don’t know what to do.” 

The words sound sorry and aching and desperate and longing all at once, and somehow they break Dean’s heart and put it together all at once. It doesn’t make sense that he wants to _cry_ , but fuck, he does--can hear it in his own voice when he replies, “It’s okay. It’s okay. I do. Read all about it a whole bunch. Just needed to know, had to know you want this as much as I do.”

He only gets the chance to kiss along Cas’ jaw a few times before he’s flipped and suddenly _he’s_ the one against the wall with Cas’ mouth on his skin, open and wet, like how they were _kissing_ a minute ago, but on his throat, his shoulders where Cas pulls back the material of his jacket and shirt more and more to get at him. Fuck he learns so fast, _so_ fast, smart good, _sexy_ boy that he is.

Okay, he really almost laughs this time--laughs at that pet name, chokes on it, a moan fighting for dominance, Cas’ age indefinable, but his body, at least, older than his a few years. But still, he thinks, _Good boy_ , at him and bites his tongue to keep trapped the bizarre surge of pride swelling in his chest because he’s got to keep in control, got to keep in control and get back on proverbial _top_ if he wants to taste Cas, and oh, he does. Oh yeah, he does. He wants a cock in his mouth, wants an actual, real cock. Cas’ cock. Because he ain’t done this either, but every time he’s read porn, he got so fricken hard he _hurt_ watching guys suck and mouth and get fucked, and just picturing Cas’ cock pulled from his pants, red and hard and leaking just for him, Cas’ cock pushing past his lips, Cas standing above him and watching as he’s blown for the first fucking time--just picturing it… Another thing. First. Taken. Claimed--

Cas grunts when his back hits the wall, though Dean _knows_ he could have stopped him if he wanted to. The fact that he _lets_ Dean manhandle him is so stupidly hot, Dean goes blind for a few seconds, working by touch when his knees hit the ground and he spreads his fingers on Cas’ hips, then thighs, blinking his eyes clear as he stares _thirstily_ at the bulge in the black. “Fuck Cas, “ he breathes, thumbing along it. He feels dumbstruck. His hands are shaking. His first cock. He’s about to get his first ever cock. He’s been wanting this so long. Been wanting Cas so _bad_. He mouths at the material covering up his prize, wanting him _so much_ he can’t even wait to put his mouth on him. He _moans_ , smelling him down here just a little bit, musky and heady. Leaving dark, wet smears on his pants, glancing up to find Cas staring down at him in shock, making these little rocking motions against Dean’s mouth that’s he’s sorta kinda _in love with_. Sorta kinda wants to tell him to keep going. To fuck him. Fuck him however he wants. Whenever he wants. Just _fuck_ him, his cheeks flaring with heat even from thinking it. From wanting it. From getting it.

He finally manages to get Cas unzipped and free, and he sways at the sight of him. Hell. _Hell_. He’s _so big_. Dean had wanted to be fucked, _wants_ to be fucked, but he didn’t think this through. Sure as _hell_ didn’t bring lube. Ugh, fuck. But he can’t even let himself think about that right now. ‘S problem for later. Yeah, later. ‘Cause right now he needs this in his mouth more than he needs anything in the whole damn world.

But still. Still he’s never fucking done this before either. He knows the methods, like, _really well_. But he hasn’t _done_ it. He might be awful.

Tentatively, he licks his lips and touches him, tastes him. Little laps and flicks, just to get started. He puts his mouth on the underside and leaves wet trails on him. Cautiously licks his tip and swishes the salty taste of his pre around his mouth and feels his own dick throb from knowing this is the first taste of cock he’s ever gotten. But he looks up at Cas. Endlessly patient Cas and murmurs, “I-I know how this is done, but--I ain’t never done it before, so…” Fuck, why is it so hard to swallow all of a sudden? “I might be bad.”

“You won’t be,” Cas replies so immediately, Dean loses his breath. “You won’t be bad. You can’t be.” He stares at Dean, hand slipping into his hair in a comfort Dean pushes needingly into. “You’re already the most amazing creature I have ever known, Dean. And everything you’re doing to me--it feels so good. I--” and it’s Cas’ turn to lick his lips, the hard, smooth head of his cock brushing Dean’s mouth. “S-Sorry,” he breathes. “I don’t know what I’m doing at all. But you--you’re amazing, and I want you, I want everything. I want it so much.” His cock nudges Dean’s lips again. “P-Please.”

Heart pounding in his chest, eyes still locked with Cas’, a sense of overwhelming _power_ and excitement gush through him. And he opens his mouth. Cas’ cock nudges in, feeling _enormous_ already with just the head.

“F-Fuck,” Cas grunts, using the curse he learned and stole from Dean’s vocabulary months ago.

Something swells in him at making him say it--because he so rarely does--as he wraps a hand further down him and lets Cas fill his mouth a little more, forcing his jaw wider, thinking, “I’m doing it. I have a cock in my mouth.” He’s aching so goddamn _much_ he pushes the heel of his palm against his own cock and grinds, too close to the fucking edge. Fuck, he’s gonna _come_. Come from a cock in his mouth like a slut. He groans, sealing his lips tight and _sucking_. 

“Oh, f-fuck Dean, that’s so--”

He drags his lips back to readjust and then pushes back down, letting his throat relax and feeling Cas nudge back there. For a second or so, he chokes, but he concentrates and relaxes again, and Cas slides in deeper, almost, _almost_ cutting off Dean’s air, which surprises him for a second, but it’s… it’s _awesome_ , everything Dean _dreamed_ about, he jerks into his own palm, almost there, almost there, so fucking close as he sucks and blows cock, he thinks it can’t get better than this, there’s no _way_.

Until.

Until.

Cas groans, hands tightening in his hair, and _rocks_ into his mouth, fucking him just a little, and Dean will freely admit that was just a whine that slipped through his sealed lips. _Yes_. Yes, oh god. Please. Oh god, that’s what he wants. The Cas that’s lost to _sensation_ , that needs and takes, and _fuck_ , if that isn’t what he gets when Cas does it again, and then again, groaning until Dean relaxes and nods up at him as well as he can, grabbing his hips while Cas _grabs_ his hair and _fucks_. 

He’s not so rough at first, just slides along his tongue and bumps the back of his throat and then does it again. Hits the roof of his mouth and makes a guttural sort of sound, but then he does it harder, hits his mouth and then turns and fucks his cheek and swears and pushes deeper into Dean’s throat, and Dean feels like he would be _screaming_ right now if he could ‘cause every thrust into his mouth is a little rougher, a little harder, hitting his mouth or pushing into the back of his untried throat until he gags and coughs and tears well up in his eyes but Cas gives him barely a few seconds to recover before he’s jerking himself into Dean again like he can’t help it, like Dean feels so fucking _good_ choking on him, he can’t help doing it again, and fuck, Dean _loves it_. This is more than Dean ever wanted, just what he imagined, but _more_ , and screaming--screaming--he would be _screaming_ because he never wants to get up from this hard, dusty floor if Cas will just keep fucking him like this until he dies.

It’s that thought--that fucked up, horny thought--with Cas’ hands tight in his hair so he can’t move anywhere and his cock pushed deep in the back of his mouth, that Dean _comes_. Eyes rolling back in his head as he rocks up into his fist and shoots in his boxers, a gargled high-pitched groan somehow finding room around Cas’ giant, gorgeous, perfect fucking cock. His mouth goes slack, but Cas doesn’t seem to care that he’s not sucking any more. And Dean’s kind of _in love_ with him for the way he fucks him _rougher_ , grabbing the back of his head to hold him in place so he can force his cock straight down his throat again and again until tears slip down Dean’s cheeks until Cas pushes as deep as he can go and _pulses_ , throbbing in his mouth and going so deep Dean can’t breathe at all, his cock jerking. Dean _knows_ he’s coming, can feel hot spurts shooting straight down his throat, can almost taste it, salty and bitter and weird, like the rest of Cas, on the back of his tongue as he’s forced to swallow, but all he can think is, _I can’t breathe! I can’t breathe!_ His hands lock on Cas’ thighs somewhere between pulling him deeper so he’s _all the way_ in and his pubes tickle his nose, or pushing him away. But his lungs start straining until he’s choking, his visions getting black spots around the edges, and pushing him away wins out. Cas only holds him there for a second longer, groaning low and _dirty_ before letting him up to cough and splutter dizzily, sucking in air like he sucked Cas’ cock.

And all he can do is sit there and heave and shake and shiver and swallow little streams of cum down his throat as aftershocks tremble through him and wetness cools on his cheeks, and he thinks, he thinks, _fuck, fuck he’s everything I ever wanted._

**Notes for the Chapter:**

> More orgasms and anal sex next chapter next chapter!
> 
> Comments are adored 💙


	2. Chapter 2

When Dean finally feels like he’s regained his breath, Cas has knelt down in front of him, his blueberry eyes hazy with lust and alight with awe. “Dean,” he says then, like he was just waiting to again be the center of Dean’s attention. Center of his thoughts. Maybe, possibly, actually right next to Sam in the middle of his whole universe. “That was… I don’t have words.” 

And okay, so it was Cas’ first blowjob ever, so maybe those words shouldn’t make Dean feel like the hottest motherfucker on the planet (or any planet), but they kinda do anyway, and it’s even better when Cas’ gaze drops to his mouth, which Dean imagines it probably all swollen and red, and licks his lips before meeting his gaze again.

“Can I… I would like to to do the mouth-touching again,” Cas murmurs hesitantly, almost shyly, totally different from the way he’d just fucked his face, and it’s so freaking unfair he can go from _that_ to this, and yet Dean feels himself cracking a grin.

“I’m gonna taste like you, but I would really like to mouth-touch right now, Cas.”

He makes this little sound like the ones he was makin’ earlier, a little growl like an angry puppy or something, and then he leans forward on his knees and grabs Dean’s hair at the back of his head and pulls him forward so their lips meet close, and rough, and fuck, it’s like he’s been doin’ this for years because he’s so, so good--god, the way he moves and turns his head and takes Dean’s lips between his own like he can’t get enough has got Dean’s heart racing and his breath stopped up in his throat, and when he finally pulls back he’s breathless all over again.

He moans--shit, it’s a whine, again--and for a second, he doesn’t even know why--something _hurts_ and feels _good_ \--and then aching pleasure shoots up his gut. And then he looks down and discovers Castiel has put a hand to his crotch the same damn way Dean did when he jumped his bones, except Dean’s already come and he’s still way too over-sensitive and ah--ah it’s almost--nearly--too much. 

“Dean,” Cas breathes, rough against his face like he’s more excited about this than Dean’s dick is, “I-I want to do the same to you. Can I do the same to you?”

“Nngh, shit, shit,” Dean gasps, rocking against his palm, because somebody other than himself is _touching_ him and it’s as _good_ as much as it _aches_ with his cock still mostly soft. But the fact that Cas is touching him, just touching him without any shyness, just putting his hands on him and rubbing against him without asking him or hesitating is _doing_ things to him because yeah, yeah, the little glimpses he’s gotten of Cas doing whatever he wants with him and being unapologetic about it is driving him crazy in the best damn way, and wants more, wants more of Cas. Can’t get enough of Cas. And he remembers, suddenly, how desperately badly he wants Cas to fuck him, but they don’t have lube--no fucking lube--and Cas is offering to put his mouth just inches away from his ass, just _inches_.

Shit--should he? Can he even ask?

“I have a better idea if-if you’re up for it.” He grabs Cas’ wrist, not pushing him away, just stopping him from moving, giving himself a chance to breathe--well, kind of, though he forgets how to the second Cas is staring at him again. His throat feels abused when he swallows. He shivers. “Do you… uhh, would you wanna… fuck me?” He thought he was beyond blushing, but he feels it right now flash across his face and his nose, and he has to fight to keep his eyes level, biting his cheek.

For a second Dean thinks that he won’t know what he means, but then Cas’ throat bobs with a swallow, and he touches mouths with Dean again, somewhere between crushing and gently, like rough and tender at the same time, makin’ his damn head spin. 

“I would-I would like--I-I’ve never, but I would. I do. _Yes_.” He looks down Dean’s body with hunger in his eyes, that--yeah, again, hottest motherfucker on the planet.

“Well, in the case--in-in order for that to happen--I, uh, need stretching…. down there, b-before I can take you, and I need something… something wet to grease the wheels, you know, and uhm. I was thinkin’, instead of blowing me, you could, uhm, maybe--if you want to--” Shit, he’s rambling, and it’s suddenly a hundred and ten degrees in here and it’s not _just_ from the way Cas is looking at him. Not _just_ from that.

“What do you want me to do?” Cas asks it all breathy, quick and eager, and Dean’s cock twitches in his pants, aching a little, stirring. “I will do whatever it is--I want to. Just tell me.”

Heat throbs in Dean’s stomach. Cas will really do this if Dean asks. Can he, though? He thinks about it… Cas between his legs, lifting his ass up…. Mouth hot and wet and noisy, right between his--

Shit.

Alright.

So he’s weak. 

But to be fair he basically creams himself every time he reads about this, and he’s wanted Cas for _ages_ , this particular fantasy rising to his thoughts a number of times… and… and… Cas is so _eager_.

“L-Listen, it’s kinda… uhh, not everyone likes doing this, okay? So if you don’t like it, or don’t want to or just--whatever, you don’t have to. I won’t be mad or sad or anything like that, okay There’s a buncha stuff we can do without this, and honestly, we could just do the fucking later when we have the proper materials, so--so--”

“Dean,” Cas interrupts, like, all fond and exasperated and stupidly gorgeous. Like usual. “Just _tell_ me. Tell me what it is.” His hands drop from Dean’s hair to his neck to his jeans-clad thighs, dragging down them slowly. “Please tell me. I don’t know what I’m doing. But you--you do. I need you to tell me.”

Dean’s breath leaves him in a whoosh. He’s so whipped. He wets his lips. “I want you to… lick me, but not my…” Oh god, it’s a million degrees in here. “My-My… where you’d fuck me.” But Cas is new to all of this, and if he’s gonna ask him, he’s gotta ask him. “I want you to lick me--down there--get me… wet and stretch me out with your tongue and your fingers until I’m--wet. Really wet, and loose. So you can fuck me.” God, his heart is throbbing so hard it feels like it’s gonna pound right out of his chest, and he puts a hand on it to keep it inside, to calm it the fuck down because words are freaking hard and he just said a lot of embarrassing ones, and yet Cas is looking at him like he just asked him if he can blow him every day, morning, noon, and night instead of this.

“Yes,” he whispers, looking Dean over likes he’s ready to eat him alive. “Yes, I-I want to try that. Very much.” He unbuttons the top button of Dean’s shirt, fingers agitated against his skin, but then he glances down, and around at, Dean doesn’t know, the warehouse, the floor, and says, “Wait,” standing and tugging off his trenchcoat and then stepping behind Dean and laying it out on the floor. And, okay, it takes Dean’s everything a second to catch up because did he just? Did he _just_? He gestures at it, and when Dean doesn’t say anything or move, says, “Lay here.”

And ok, ok, that feeling in his chest, what is that? You know what? No, no, he doesn’t have time to examine it, all hot and fondue-like and bright because, yeah, Cas _has_ just. He’s literally lain down his coat for Dean to sprawl on so that he can lick him open, and he needs that so bad right this second he might spontaneously combust. And, okay, so a soft grin stretches his cheeks--he’ll allow that--but nothing else, nothing further, not until after Cas has fucked him rough and sore and splattered cum all over his coat, which---okay, fuuuck. 

Something pings inside him as he scrambles backwards and starts undoing his buttons before ripping his shirt off and watching one stray button bounce away on the hard floor, because okay, okay, cum on Cas’ coat. Cumming. All over Cas’ coat. Cas’ favorite goddamn coat, that damn coat he wears everywhere, never takes off almost. It’s like the thing everybody sees first (well, after his stupid hair and crazy eyes and those pink whip cream lips), and just feeling it under his palms, still warm from Cas and _soft_ , he _groans_ , knowing he’s gonna mark this up with his fucking cum where everybody can fucking see and dying inside in the best possible way.

“Come on, Cas,” he pleads, working his boxers and pants down over his hips and kicking them off as Cas watches him with his cock still sticking out of his pants. And… his cock. His _cock_. Which is hard. Still hard? Hard already? Hard? Cock? His cock is _hard_!? “Shit how are you--” he breaks off. “Don’t you have refractory periods? Why are you--” But his gaping is ignored for Cas dropping to his knees with these hooded eyes and lowered brows and parted lips as he puts his hands on Dean’s knees and pushes them apart and okie dokie, Dean can shelve this for later. Later is good. Later is _awesome_. Later is-- _oh shit_ \--Cas is licking his dick. Attention customers! Cas is licking his dick! His--oversensitive, twitching, sticky, cum-covered-- _Nnggh-gaaahh!_

“Cas,” he gasps, digging a hand in his hair to ground himself. His wet, pink tongue is dragging up him like he’s pictured so many times, and it’s so much more than he ever imagined, having Cas’ tongue on him, hot breath blowing against his aching cock. It almost _hurts_ he’s still so sensitive, claws of shooting pleasure in his groin and gut with every hungry swipe of that tongue, and shit, his cock is hardening, twitching slowly, _achingly_ , but yeah, fucking twitching to life as Cas swirls around his head to get every last drop of cum and then mouthing at the base of his shaft before sucking his balls--which Dean didn’t even _teach_ him, shit shit, how does he _know_ \--and then, _then_. 

Dean’s hands slips from his hair to drop to Cas’ coat beneath him to steady himself, leaning back and spreading his legs wider as a cool, hot tongue drags down his taint and then swipes at his hole. It’s weird and wet and tingly, Cas’ tongue almost sandpapery rough in a really bizarrely good way, but the fact he’s doing this, actually, actually doing this in the first place--Dean’s got somebody between his legs _licking his asshole_ \--turns him on so damn much he jerks his hips at nothing, fighting back a moan, fighting to keep from grabbing himself and _jacking_. “Cas, Cas, Cas, god--feels good. Feels really really--oh shit--” He can’t see what he’s doing and the feelings are all somehow powerful and muted at the same time--like they feel incredible, but he can only decipher some of them-except when--when there’s pressure and Cas is, oh, Cas is pushing _at_ him, pushing--almost pushing _in_ him--that he feels clearly and whines. “ _Caa--aa--as_ ,” he whines, making sounds he’s never made before, gasping for air, for breath, for _something_ to fill him when Cas lifts his head to look at him, eyes dark and lips wet.

“Am I doing this right?” he sounds all gravely like he’s the one whose throat got fucked, and god, oh _god,_ Dean can’t take this. Feel so good, feels too good, everything, everything Cas does to him. Hands on his thighs, big and heavy and hot, breath ghosting over his stomach, tickling the hairs just below his belly button.

“ _Yes_ ,” he breathes. But then, “I dunno, I dunno. Never--never ever felt anything like this, but all I know is it’s fucking _amazing_.” 

Cas’ lips twitch and his eyes smile, except this time, he draws a hand up over Dean’s hip, grabs his definitely-fully-hard cock and jerks it. Base to tip, still all moist from Cas’ tongue--just jerks it then slides back down and does it again, his mouth going back to Dean’s hole, flicking and drooling and sucking and wet, and it’s too, too, too much. “Fuck, fuck,” he curses. “Cas, Cas, Cas,” He surges up into the fist wrapped around his throbbing dick, falls back down on Cas’ tongue, probing him open, pushing inside. “Why are you--” he gasps, whining a little bit, deep in his throat. “So fucking good at this?” But even as he asks it he knows why, or at least part of it. All the squeamish reluctance or shyness that a normal human being would have Cas never learned, and he’s just going at him like he’s a fucking ice cream cone. And the hand on his dick--the hand on his dick--he’s such a fast learner, jacking him like Dean sucked him earlier--careful attention to the head, swirling, twirling, playful little eager thumb imitating his tongue and then sliding and pulling back up two-three times. God bless him, such a good student, such a good, good boy.

“Fuck!” The curses just keep pouring from his mouth, stuttered and sloppy and repetitive, but he can’t stop, he can’t stop, what can he say? He’s gonna cum again. He’s killing him. “You’re killing me.”

It takes him a second to realize that was not the right thing to say to an alien being who takes nearly everything totally literally, but after about two whole seconds when everything has stopped, mouth and hand retreated and Cas reappearing with shiny, wine-pink lips and eyebrows that speak a thousand words of turmoil, it clicks. “Not really! Not literally!” he exclaims, a laugh bubbling up his throat and barely staying inside. Oh god, now is not the time to laugh about his alien not-boyfriend thinking he’s literally killing him when Dean screams gibberish in ecstasy. Now is _not_ the time. But _fuck him_ because he giggles anyway, all delirious and drunk on Cas and fucked, his groin making these little thrusting motions against the fucking air as he nearly whines to get Cas back on him. “It’s-It’s an expression. I’m okay, I’m _great_. I promise! You’re fucking amazing, okay? Please, please, don’t stop. Please, please, please,” And fuck him some more because he’s resorted to begging, the blush in his cheeks spreading down his chest, but he can’t stop. “Please, please, Cas. Please don’t stop. Need you. Please.”

Tentatively, like Dean might explode or something, he reaches out a hand and jacks his dick cautiously, and fuck, fuck, he really needs to remember that _now is definitely not the time to laugh_. But then Cas narrows his eyes and does it again, and a giggle spills out. And then another one. Damn _giggles_. “Cas,” he chokes, barely holding in the laughter, his stomach vibrating. “C-Cas, man I’m okay. Really, really okay. Not gonna die--from you goin’ down on me. Cross my freaking heart.” And oh shit he’s laughing now, he can’t help it, has gotta pull himself into a sitting position just so he can grab Cas’ ears and kiss him full on, hard and deep--as deep as he can when he’s fighting back ridiculous laughter--before falling back down again and spreading open his legs. “Come on, man,” he pleads again, biting back the _you’re killing me_ on the tip of his tongue (which got him into this mess in the first place) for, “Need you so bad.” 

Those fricken eyes he likes so damn much darken, those lips parting, and he nods slowly, seeming finally reassured. “Okay,” he breathes, not much of a talker himself, which is totally cool, because Dean fills that silence himself just fine--and then he’s back, leaning over his stomach, breath warm and hot as he first kisses his belly button and then a little lower, glancing up at him with those hot eyes that make Dean wanna scream. Then he goes lower, disappearing between his legs and picking up right where he left off, leaving Dean a whining, choking, squirming mess with his talented freaking mouth and attentive hands.

He doesn’t know how long he goes on, but he’s gotta be honest, he doesn’t thing it’s all that long when his orgasm starts encroaching. Like, he really shouldn’t be coming right now, relatively soon after his last orgasm and all, but Cas is just relentless and tireless and so, so awesome. He literally doesn’t stop, just keeps licking and getting him all wet just like he told him to, and by now, he’s really stuck his tongue _inside_ a few times and fucked him with it--and if that’s not the hottest thing that ever happens to him, he’ll be surprised--still Jerking his cock off and on in between, when he could spare the hand, and now he’s got his first finger inside alongside his tongue, the first person besides himself to _ever_ put anything up there, and Dean is just… he’s just done. And he knows he shouldn’t come, probably, right? He should wait til Cas is inside him, but either way, he ain’t gonna last, and he just-just isn’t that strong a person, alright? “Cas, Cas, don’t stop, oh--g-g-g--” Breath sucks into his lungs as Cas circles his cock with his hand and finger and fucks him while licking away at his twitching rim and oh fuck. “G-Gonna come!” he shouts. “Gonna--” But in the brief moment Dean thinks that, okay, this is good that he’s announced this, this is good--because Cas will stop or slow down and back off and give him breather before fucking his brains out--that brief moment is crushed when Cas makes this sound like, you know the one, yeah, like when he was fucking Dean’s mouth, like when he sounded more feral than human, just like that. Right, so he makes that sound, yeah? And then he increases the tempo about ten times. So that slowly flicking tongue? Grinds into his ass. That carefully probing, thick-as-fuck finger? Pounds into him, almost rough, almost. And that hand slowly teasing his dick, pulling on him pace for pace? Wraps tighter and _jacks_.

Did he mention he’s done? Also, also, did he remember to mention that he’s not all that strong a person, not really? Right, good. So then you’ll understand when he’s shouting wordlessly and coming in seconds, _shoved_ over the edge by this guy he can’t fucking get enough of. His hands pulling from him the first orgasm any guy other than himself has ever given him, and he’s shouting it at the damn ceiling because it’s the best thing he’s ever felt in his _life_. This, this right here. Best. Fucking. Orgasm.

His back bends, his hips thrusting up into the air as he shouts and cum spurts hot from his cock in messy splurges, dripping down on his stomach and Cas’ hand and, oh god, his trenchcoat. His trenchcoat. He’s _sure_ he got at least a dollop on his trenchcoat, and that makes him spurt just a little bit more, a little more thinking about it on his hand and his trenchcoat, his cum all over Cas, fuck. It’s a thing, okay? A thing, he’s apparently obsessed with, shit.

He orgasms twitchily _forever_ , Cas stroking tremors from him until he feels like he might literally, actually die, before he stops. Or no. No, not stops, apparently, but pauses. It takes a second when he feels a brush of fingers on his stomach--because his eyes are closed; his entire body boneless--but then he feels pressure down below, and fingers--two of them--pushing wetly and hotly into his oversensitive, aching ass before he realizes it was just a brief, brief--far too brief--respite. But they do leave him again…. And then fingers swiping across his stomach again... Why his stomach? Before pressing something wet and slick and hot into his ass--and oh. _Oh_. Oh, he’s such an idiot, but please blame that on the two earth-shattering orgasms he’s recently had and his overwhelmingly over-sensitive, lax body accepting Cas’ fingers, that he’s only _now_ getting that Cas is feeding his come into him like lube. 

Yeah. Yup. That’s what he’s doing. Just pushing it inside and fucking his fingers in his quivering hole a few times before exiting and finding another smear, another dollop. Okay. Okay. _That’s_ what he’s doing.

Dean whines and shakes. Trembles, really because he can barely make his limbs move, overwhelmed, and yet still desperately turned on by Cas finger-fucking his own cum inside of him. And the way he’s just _doing it_ , as if Dean’s fucked out body is easier to manipulate, and oh god. Dean can’t get hard--he can’t get hard again. Not this fast, it’s not physically possible. And yet. And yet he wants Cas. He still wants Cas so bad. Wants him to fuck him. Wants him to _use him_. Wants both of their virginities taken tonight. Wants that to be his. Wants Cas to fuck him full and fill him up. More cum. More cum fed into Dean’s body to spill out onto Cas’ coat.

“Fuck me,” he breathes, and he’s surprised at the way his voice sounds, all thick and low and rough and dry. He feels lips on his stomach and forces his eyes open to see that gorgeous face looking at him over his soft, fucked out cock. “Want you to.”

“Want you,” Cas says. “Want to fill you. Want to put myself here,” he pushes his two, cum-covered fingers deeper to emphasize his point. Ya know, in case Dean could ever miss what, exactly, he means, even in the state he’s currently in.

“ _Nnngh_ , want you to,” he repeats, weakly arching against those fingers inside of him. “Fuck me, Cas. Cum inside me. Stuff me _full_.”

Cas groans at his words, his fingers retreating, and for a second Dean wonders where he’s gone, his lazy eyelids fluttering, but then there’s a rustle of clothing and a belt clunking on the ground and he realizes that Cas is stripping. Stripping for him, _mmm,_ fuck. He forces his eyes open but only gets a brief chance to see his strong shoulders and lean arms and solid chest, a hint of hip bones he could cut his freaking tongue on if he ever got the chance to suck on ‘em, which, yeah, okay, next time he’s _definitely_ doing that. But then Cas is back, he’s kneeling, and he can just see his jutting, fucking cock, thick and veiny and _hard_ , and did he mention thick? Because yeah, holy fucking _shit_ \--before Cas is over him, palms flat on his coat, just outside his waist, heat sinking into his body, raising his damn blood pressure like Cas’ nearness always seems to do, that hard thick thing nudging against his ass cheeks, which _hell_ , a cock is nudging his freaking ass cheeks! It’s about to happen. It’s actually, literally about to _happen_. He’s gonna get fucked, for real, by Cas. Oh hell.

His molars sink into his cheek, maybe, sorta, kinda tentacle-wrapping his arms around Cas the second he gets close enough. But he just wants to feel him okay? Hold him. He has come stupidly hard twice in the recent past because of this gorgeous fucking dude, and he’s about to fuck him, and yes, alright, he’ll admit it: he’s a cuddler, so, _sue him_. 

Also, also, Cas is really really close and hot as _hell_ , has Dean mentioned that? Wild dark hair and cotton candy eyes and those damn pink lips--not to mention that gorgeous cock he’s about to sink into Dean’s cherry-pink core. God, he can’t stop looking at him. God, alien or not, he’s the hottest thing Dean’s ever seen, and he’s the luckiest sonuvabitch on any planet.

Even as he thinks it, Cas reaches back, and that giant, hard prick nudges between his cheeks and at his hole, and Dean is so fucked out, so lax, and so licked wet and cum-slick, he pops right in. Ha, “pops right in.” Is that hilarious or is that just Dean being crazy again? ‘Cause, ya know, he just popped his cherry. And he doesn’t stop, not for a second, doesn’t give Dean a breath even for the breath _he’s_ holding as he forces himself to stay relaxed while Cas slowly slides himself all the way in, in one, long, steady drive until his balls nuzzle up against Dean’s ass and he’s pushed so damn deep inside of Dean can taste him in the back of his throat.

“Oh, god, _Dean_ ,” he purrs, all husky and breathless and almost pained like the way Dean feels with Cas’ actual fricken cock all the fricken way inside his tender pink bub. 

“Shit,” he breathes. “Shit, Cas.” Probably making claw marks all over his neck.

“Dean,” he breathes again, pulling out just a bit to fuck back in with his name. But then once wasn’t enough (I mean, obviously) so he does it again, grunting his name like a chant of pleasure as he fucks himself in. He _still_ doesn’t even give Dean a chance to breathe, to get used to this burning hot intrusion making room for itself in his guts--he doesn’t know better, of _course_ he doesn’t--but it’s okay, it’s okay. Dean doesn’t want him to stop. It hurts, some, with that giant thing fucking him _raw_ , but it hurts so _good_. Like, okay, maybe he’s nuts, maybe he’s a masochist--he doesn’t fucking know. Maybe he’s just a freaking Cas addict, but he wants it all, wants everything--even the pain, if it’s from Cas--doesn’t want him to stop--and he doesn’t. He’ll take it, take everything, take anything Cas wants to give him, and beg him for more afterward. ‘Cause Cas is here for good, and he’s finally _Dean’s_ , and maybe Dean can’t be the family that left Cas behind, but he can be _a_ family, a good one, if Cas’ll let him.

“Harder,” he grunts in his neck, breathless, already breathless, from Cas fucking inside of him. Oh god, that cock inside of him. It’s so hard, so deep. He tightens up around it, just to feel every inch of it fuck into him and gets a shuddering moan in reward.

“Dean… Dean… feel so… good,” Cas’ words are like sighs and grunts all twisted up into one, all pleasure, all good. He nips at Dean’s jaw, biting at his skin more than he is kissing, nibbling down to his ear, planting his mouth on one side of his throat and staying there, half mouthing, half biting, like he just has to translate his pleasure somehow, some way into Dean’s skin. And Dean’s never felt so _possessed_ in his life.

And then Cas _hits_ it, hits _it_ , that magical place inside he’s only ever managed to reach with a toy he bought for cheap off the internet once, and he _shouts_. “Oh god! Right there! Oh god, that feels so good!” And he cries, tear tracks falling over the salt already on his cheeks and dripping into his hair because it feels so good, feels so right. Cas on him, on top of him, inside of him, pushing him into his soft coat and fucking him raw and hard and senseless, and now that he’s found it, that hot, fondue core of heat inside of Dean, he keeps _hitting_ it, over and over.

Such a fast learner. 

“ _Caassss_ ,” he moans, utterly on the _edge_ of pleasure, overwhelmed, everything hard and fast and too much and not enough. It’s pain and pleasure and ache and awe all bound up together until he feels like he’s going to explode if Cas fucks him one more time, but he does, he fucks him one more time and two more times and again and again and again, and yet somehow he holds Dean together, he holds him together with his hands and his lips and his teeth and his body pressed into his and his cock fucking him to pieces. And then he wraps a hand around Dean’s weak, twitching cock and _strokes_ him, and Dean screams. He can’t come again, he can’t. He can’t, he can’t, he can’t, he--

“--can’t, I can’t, I can’t, I can’t--” 

He’s full on _crying_ now, sobbing into Cas’ shoulder, but Cas doesn’t stop, doesn’t stop fucking him, stroking him, kissing him, holding him, and Dean doesn’t think it’s possible, but somehow his cock gets all the way hard and then Cas whispers, “Come for me,” in his ear, and like it was just waiting for the command, his cock _comes_.

Watery semen dribbles free, his back arching with blinding pleasure rippling over him like a waves, his knees locking up around Cas’ waist, toes curling and pointing, and then Cas is fucking inside of him and grunting, groaning, saying his name over and over and over, and then _he’s_ locking up, way up in Dean, and he can just feel the spread of heat, liquid and lava in his guts and knows Cas has come, _finally_. He’s come. Inside of Dean. Just like he wanted.

**Notes for the Chapter:**

> Comments are adored 💚
> 
> Sweet, precious fluff next chapter! 💕


	3. Epilogue

Hours, days, weeks could have passed for all Dean knows when he regains consciousness.

His entire body is sore, but not like the kinda sore from walking five miles to school like they did in that one town for a month, or the exhaustion after fighting freaky, shape-shifting aliens in the ruins of their ship soon after meeting Cas. No, this is actually much different. An achey, sated kind of sore that reaches depths inside of him he didn’t even know existed. The kind of sore that makes him want to sprawl, naked and warm, like a cat. Or unlike a cat, sink into a bubble bath and float for a goddamn hour.

Or, you know, lay wrapped up against a firm body with arms to hold him close, fingers that draw unknown languages on his skin, and lips that leave barely-there mouth-touches on his hair. Which… okay, is Cas really this perfect?

The foreign, salty musk from his skin, mixed with human sweat and the heady smell of sex, breathes up his nose and puffs through his parted lips, delicious and somehow already familiar. 

His head rests on an arm, makeshift pillow, while another arm has crept around his back and holds him close. There’s the weight of a leg thrown over his and a nose pressed to his head, and if he just had a bed to lay on rather than the hard floor beneath Cas’ soft, warm coat, he’d be in _heaven_ right now.

As it is, he lets out a soft groan and a whimper as he shifts slightly and stretches slightly, his ass twinging with pain and his throat feeling rough and abused, and well shit, as sated as he is right now, arousal pulses in his stomach. Yeah, okay, so maybe they were a little unprepared and fucked a little too rough, but god was it _hot_. God it felt good. Feels good. The fact he’s gonna feel Cas all over his body the next few days has a giddy grin climbing his lips. 

“Dean,” Cas breathes against his hair as he comes to. “You’re awake.”

“No shit, Sherlock,” he hums, not yet willing to open his eyes, but turning his face up into Cas’, finding himself nose to nose and nestling in. “Mmmm,” he hums again, taking slow, deep breaths of Cas’ scent, now that he’s so close. Now that he’s allowed to. 

“I was worried,” Cas murmurs. “Are-Are you okay?” That big hand of his closes over his jaw, covering, like, half of his face, and Dean turns into it happily. 

“I’m ‘mazing,” he breathes, pressing kisses to Cas’ palm and feeling this imperative need building up inside him to kiss every inch of Cas. Cas. His Cas. His good one.

Cas’ scruff tickles Dean’s lips, but he presses kisses over his jaw and chin anyway until he can reach his lips and melt into them, Cas’ arms wrapping him up again and squeezing him so close and tight he almost can’t breathe. He doesn’t give a flying fuck, though. Who needs air? Not him. Not when Cas is holding him like he’s everything. Kissing him like he will never get enough, lips fitting to his like a freaking puzzle piece coming together. And shit, shit, that sappy, melty, fondue thing is back again. And now that he’s not losing his freaking mind to lust, he actually has time to consider it. And damn, it can only mean one thing and that’s that he’s got feelings for Cas. _No shit, Sherlock_ , echoes in his head, except this time, it’s Sam’s voice. _Shove off_ , he snipes back. So… yeah, he doesn’t just want Cas to fuck him into next month. Well, not _just_ that. He’s got feelings for him. Real feelings, really _big_ feelings. Maybe he’s not quite ready to name them yet, but he can admit to himself they’re there. Oh yeah…. they’re definitely, definitely there.

Cas makes this little moan Dean’s crazy about when he finally breaks the kiss so they can breathe puffs of air on each other’s skin. Those stupid cotton candy blue eyes look at him with a bunch of stuff in them Dean can’t name. “Are you sure you’re alright?”

He grins, can’t help it. “I’m fine, dude. You just fucked me senseless for a while, and I conked out. I mean, god, you made me come three damn times, wha’ja expect?” Those eyes he loves so much squint, and Dean interrupts before he can form words. “Don’t answer that,” he says, chuckling.

He’s so close to him, he can barely see his whole face, but he doesn’t wanna move. Preferably not for a week, but that’s a matter for later. Cas skin is unearthly hot under his hand where he slides it over his chest and ribs, giving himself a moment to find words. “Listen, uh, I know you’re kind of inexperienced in… all we just did. Realistically, I probably definitely shouldn’t have jumped you like I did, but…” he bites his cheek. “It was okay… right? You liked it? All of it? Never wanted to-to stop, yeah?”

Oh fuck him and his head tilt, makin’ him wanna kiss him all the damn time. “Dean, I… I don’t even have the words. It was incredible. I never wanted to stop for even a second.”

Okay, so the way Cas jumped on board, he probably shouldn’t have doubted, but Dean lets out a breath he didn’t know he was holding anyway. “Good. That’s… great.”

“For a very long time I’ve… admired you,” Cas goes on, seemingly picking his words carefully. “Wanted you. Wanted to be… closer to you. Wanted to be with you all the time.” Oh, is this what it feels like for your heart to stop beating? “But there never seemed to be a good time until now. And besides, I didn’t know what to do or how to get everything I wanted… Or whether you would even want the same with me.”

“Oh god, Cas, I did. I do. I’ve probably wanted you as long as you’ve wanted me, if not longer, and I wanna do all of this over again… hopefully a _lot_.” He chuckles, wincing when his ass twinges. “You know, after I’ve had a day or something to recover a bit ‘cause you really fucked me senseless.” He laughs, and Cas’ eyes sparkle, his mouth twitching. “Shit, now that you’re here, for real, if-if you want, that is… You can stay with us. Me and Sam and Bobby. Bobby will be fine with it, and… I can teach you whatever you haven’t yet learned about earth. And sex,” he winks, belying the pounding heart in his chest.

“I want that very much. But,” Dean’s heart drops somewhere through the damn floor. “There’s something I don’t think you’ve noticed that you should know about me.”

“Um. O-Okay?” Yeah, that’s a freaking awesome way to make Dean not nervous.

“What I said before was true… This is my form now, and I can’t shift. Fully.” Cas looks like he’s just delivered news that he has a third arm behind his back or something.

“What the hell does that mean?” Cas’ eyes flash with something that looks like worry, and Dean instantly hates himself for putting it there. “Sorry, sorry, I didn’t meant to be harsh, I just… What do you mean?”

“Well…” he says slowly. “I can’t fully shift, but sometimes when I’m around… other species I may develop… quirks.”

Cas’ arms tighten around him like he’s afraid Dean will slither away at this revelation or something. “Yeah, still not totally gettin’ what you mean.”

God he’s cute when he’s thinking… That indent between his eyebrows? That little pout? Hell…

“I mean… say I spend time with a feline. I may then…”

“Wanna cuddle on me all day?” Dean chuckles, still distracted by those lips, but when Cas doesn’t smile back, he blinks. “Wait, you might really wanna curl up on me like a cat?” A shoulder lifts in a weak shrug, and Dean about chokes on his spit laughing. “Okay, and?”

A skeptical look crosses Cas’ face. “’And’?”

“Yeah, ‘ _and_ ’.” Well now he’s just picturing that cute as fuck nose with a pink triangle painted on and whiskers on his cheeks. And a tail. Definitely can’t forget the tail. He taps that nose. “Hell, maybe we should get a cat if it’s gonna make you wanna be this close to me all the time.” He grins in spite of the light blush he can feel dusting his cheeks.

“My incisors may lengthen.”

“Okay.”

“My fingernails may seem more like claws!”

“Cool.”

“And Dean, if I’m near a dog--”

“You’ll sniff my butt? Hate to break it to ya, but--” Dean flashes a grin at him.

“No,” Cas replies, looking very serious indeed. “My penis develops a knot.”

…

… Blink blink…

Well… crap.

And here he thought he had that little blush under control, but suddenly he’s remembering all those dirty, dirty books he’s read with alphas and omegas and slick and knots and… Oh fuck yes.

“We are gonna have so much kinky sex.”

Cas lets out an exasperated sigh. There was even nearly an eyeroll in there. Dean’s taught him so well. “None of this bothers you?”

“Mm,” he does actually pause to consider this for a second or two, but… “Not really?” he decides, kissing his cheek. “Dude, I already knew you were an alien, ya know. ‘S not like I’m goin’ into this blind.” He kisses his nose, just because he can. “You’re already supernaturally strong and talk to, like, flowers, and animals and shit.” Kisses his other cheek, right beneath his eye, then again a smidge lower. “Why not fuck me full of cum on your knot?” Kisses the space between his nose and those lips. “I want you. All of you.” He looks at him honestly. God he’s so gorgeous. He’s so, so, so whipped. “Don’t really know why you want me, but you say you do so I’m just gonna say _thank fuck_ and not argue.” At the end of this mini speech, he settles back comfortably and sits there quietly while Cas studies him, totally content to just be here with Cas while he works through whatever anxieties he’s got. Dean’s not gonna go anywhere. Besides, remember that not moving for a week thing? Even if he does kinda need a shower soonish since he’s gradually realized he’s covered in crusty jizz. But he’ll be okay for a while.

Finally, Cas nods his head once and says, “Okay.”

Dean’s heart maybe flutters a little at that one word. “Okay?”

Those dark locks tumble over his forehead when he tilts his head and looks at him with this goofy expression on his face. Like, he’s not smiling, not really, but his lips are the tiniest bit quirked, and he seems about to tell a joke or something. “If you say you want me, I am not going to argue.”

He snorts. How could he not at the words Cas has just mirrored back at him? And he grins, big, bright, unbreakable, unbeatable because this is really, really real now. It’s really really real. Cas, _good_ Cas, loyal Cas. _His_ Cas. He doesn’t have a clue what the future will really hold now. Not anymore. But he doesn’t give a flying fuck because his family is Bobby and Sammy and now it’s Cas. And for once, all he’s gotta do is live. And be happy. 

“Such a fast learner,” he gloats just before Cas’ mouth touches his.

**Notes for the Chapter:**

> Thank you so much for reading ❤️❤️ I hope you enjoyed it as much as I did 😏 *eyebrow waggle*
> 
> No, you don't understand, comments are ADORED *big eyes* They feed my soul <3


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